A complete census has been prepared of over 1,000 individuals living in Graciosa Bay on Santa Cruz in the British Solomon Islands. The entire population has been tested for hepatitis B antigen (HBs Ag) and antibody to HBsAg. The frequency of antigen was 11 percent while that of antibody was 21 percent. This data is being correlated with the census in a epidemiological study of the genetic, environmental and cultural factors which affect the establishment of the hepatitis B virus (HBV) carrier state. Another field trip is planned for 1976 in which the entire population will be retested in an effort to define which of these factors affect the persistance of the carrier state. BIBLIOGRAPHIC REFERENCES: S. Mazzur, Subtypes of HBsAg in Oceania, Proceedings of the First International Workshop on HBsAg Subtypes, Bibliotheca Haematologica 42, 1975, in press.